bump version to 2.5.2

Merge pull request firmata#259 from firmata/v2.5.1

Bump version to 2.5.1.

Merge pull request firmata#244 from firmata/v2.5

prepare for v2.5 release

typos and clarifications

Merge pull request firmata#191 from firmata/ethernet

Add StandardFirmataEthernet example

bump version

Merge pull request firmata#186 from firmata/analog-reporting-fix

prevent analog reporting during system reset

bug fix: moved call to blinkVersion to correct location

added support for Arduino Due and Teensy 3.0. Added unit test suite